In communication networks, e.g., based on the Internet Protocol (IP) and the Transmission Control Protocol (TCP), various kinds of data traffic is transferred. Such different kinds data traffic may differ with respect to their sensitivity concerning delay which occurs while data packets of the data traffic are forwarded through the communication network. For example, for data packets of a file download the delay of the data packets is typically not very relevant. However, in the case of realtime data transfers, such as multimedia streaming, excessive delay of a data packet may adversely impact the user experience because typically data packets need to be available at the receiver at a certain time, and later received data packets are useless.
A known way of addressing such different delay requirements is to strictly prioritize the delay sensitive traffic data over the other data traffic while at the same time limiting the delay sensitive traffic to a maximum bitrate to avoid starvation of the other data traffic. However, in this case the sharing of bandwidth cannot be controlled in a satisfactory manner. For example, it is not possible to address a scenario where certain data traffic is not delay sensitive, but on the other hand has high importance and should therefore be treated with high priority.
In “Rainbow fair queuing: theory and applications” by Zhiruo Cao et al., Computer Networks 47 (2005), a method is proposed which allow for fair sharing of bandwidth on the basis of a “color” label assigned to the data packets, without requiring separation of the data traffic into different flows. The color label is used in a router for controlling discarding of data packets. However, in this case all traffic will experience substantially the same delay. Therefore, in order to meet a requirement for low delay, such low delay needs to be achieved for all traffic. However, providing such low delay also for non-delay sensitive traffic may result in a throughput degradation, e.g., because larger buffers are required for optimal TCP operation.
Accordingly, there is a need for techniques which allow for efficiently controlling the handling of different kinds of data traffic.